Published 02 September 2026 | Nature & Environment

TL;DR: Research by the University of Jaen found that semitransparent solar panels can cool greenhouse interiors by up to 5°C and reduce irrigation needs, offering a possible route for more efficient protected agriculture in Almeria .

Solar panels and cooler greenhouses

Greenhouses fitted with semitransparent solar panels could help address two of the main pressures facing protected agriculture in Almeria: high summer temperatures and limited water availability.

A study by the University of Jaen has found that the panels can generate electricity while creating cooler, more humid conditions inside the greenhouse. In the trials, this reduced water loss through evaporation and lowered the amount of irrigation required by the crops.

The findings have particular relevance for Almeria because the province’s agricultural model operates in conditions similar to those tested by the researchers: a semi-arid climate, low humidity and high summer temperatures. However, the experiments themselves were carried out in Jaen rather than in Almeria.

Cooling the greenhouse environment

The research team examined two commercially available semitransparent photovoltaic technologies using several experimental mini-greenhouses. Tomatoes and lettuces were grown successively over five crop cycles, allowing the researchers to compare the conditions created beneath the different panel types.

The panels reduced indoor temperatures, with peak reductions of up to five degrees. They also increased relative humidity inside the structures. Together, these changes reduced the loss of water through evaporation, which lowered the crops’ irrigation requirements.

The study estimated that water needs fell by around 31% with cadmium telluride panels. The reduction was above 60% with amorphous silicon panels. These figures come from the experimental work and indicate the differing performance recorded between the two technologies.

The panels’ shading effect is central to the result. By limiting the amount of solar radiation entering the greenhouse, they can reduce the heat building up inside. At the same time, the modules allow some light to pass through, meaning the system must balance electricity generation with the light needed by the plants.

Sharing space for food and power

The approach forms part of agrivoltaics, a model that uses the same area to produce food and renewable energy. In a greenhouse setting, semitransparent photovoltaic modules can serve more than one function: they provide shade, influence the growing environment and produce electricity.

That electricity could offer farms an additional energy source, although the study presents this as a possibility rather than a completed change to agricultural operations. The research focused on how the panels affect greenhouse conditions, crop light and irrigation demand.

The question of light was one of the main issues considered by the scientists. Plants need suitable radiation for growth and photosynthesis, while the panels need to intercept enough sunlight to produce electricity. The researchers therefore examined how the different modules altered the light reaching the crops.

Light quality matters

Although the panels reduced the total radiation reaching the plants, the study found that some modules allowed blue and red wavelengths to pass through more readily. These wavelengths are particularly used by plants during photosynthesis.

This distinction is important because the impact of a panel cannot be measured only by how much light it blocks. The type of light that continues into the greenhouse also affects the conditions experienced by the crop. The results suggest that panel design plays a significant role in finding a workable balance between shading, plant requirements and solar electricity production.

The two technologies tested did not produce identical results. The recorded differences in irrigation reduction show that the choice of photovoltaic material can influence the environmental conditions inside the greenhouse and the water needs of the plants.

Relevance for Almeria

Almeria has not been presented as the location of these trials, but the researchers point to similarities between the Jaen test conditions and those found in the province. High summer temperatures, low humidity and a semi-arid climate are all relevant to the region’s greenhouse agriculture.

For that reason, the study offers a potential line of research for Almeria’s protected cultivation sector. Semitransparent panels could help moderate greenhouse temperatures, reduce irrigation needs and provide electricity from the same covered surface used to grow crops.

The findings do not establish how the technology would perform across Almeria’s different greenhouse systems or under local operating conditions. They do, however, show why agrivoltaic designs are attracting attention as agriculture looks for ways to manage heat, water and energy demands together.

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